Polymer melt-blending has been used for decades in the area of non-absorbable industrial thermoplastic, heterochain, and homochain polymers to produce different polymer blends (or polyblends) exhibiting a range of physicomechanical properties to meet specific requirements of a broad spectrum of industrial and medical products. However, because of the chemical nature of the non-absorbable components of these polyblends, practically no chemical interaction takes place upon melt-blending of the components and there has been virtually no interest in achieving such interactions. And with the development of biomedical absorbable polyesters having reactive chains, more attention was directed to the maintenance of the integrity of these chains during the melt processing of crystalline block and segmented copolyesters, where uncontrolled ester-ester interchange can lead to a decrease or total loss of crystallinity. Subsequently, the lack of understanding and ability to control the ester-ester interchange reaction in molten absorbable polyesters has discouraged investigators of the prior art to exploit melt-blending of different polyesters as a means to form absorbable polyblends with unique properties, as has been the practice with non-absorbable polyblends. Interestingly, one of the present inventors and his earlier coworkers ventured to use melt-blending to yield two-component composites under conditions that did not alter the initial physicochemical properties of these components, which independently co-existed in the solid state (U.S. Pat. Nos. 4,741,337 and 4,889,119). More specifically, the latter prior art dealt with surgical, fasteners comprising a glycolide-rich blend of two or more polymers, one polymer being a high-lactide content polymer and another being a high-glycolide content polymer. The blend as a whole contains from 65 to 84 weight percent polymerized glycolide with the high-glycolide content polymer constituting at least 50 weight percent of the blend. Regrettably, development of these blends failed to lead to a marketable product of the sought medical devices. This failure was attributed to the high content of the fast-absorbing glycolide-based major component of the blends and uncontrolled physicochemical events that might have prevailed during melt-blending, resulting in non-predictable changes in the device properties when used in the intended biological environment. Such unfruitful use of melt-blending provided the incentive to pursue the study subject of the instant invention that deals with the use of slow-absorbing, high lactide-based segmented copolymers as the principal component in specially selected compositions that permit controlling the extent of the ester-ester interchange reaction and hence, the molecular intermixing to produce multiphasic crystalline solid materials with predictable properties for use in new or existing forms of medical devices.